Mirage B3060 Brown face burnt circuit

Discussion in 'Amateur Radio Amplifiers' started by N8ZI, Aug 20, 2019.

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  1. N8ZI

    N8ZI XML Subscriber QRZ Page

    Someone else here kept telling me I need one as he said mine was missing. Now when I trace back I find that cap at the other end of the coax.
    So apparently my burnt section is nothing more than another wire to the circuit board ground. Basically tying the circuit board ground to the aluminum chassis ground.
    Here is a photo of the other end of the coax with the capacitor between the center conductor and ground.
     

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  2. WB3BEL

    WB3BEL Ham Member QRZ Page

    That's what I thought. I doubt that part would go bad. Maybe the power flatness is the input and output cap adjustment or maybe something else.
     
  3. N8ZI

    N8ZI XML Subscriber QRZ Page

    I have 2 people telling me mine is vaporized into oblivion yet I find it on the other end of the coax where your Mirage 3016 has the cap. If your amplifier only has a wire where my burnt one is, then I will just add a wire.
    Here is another angle of my burnt section.
     

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  4. N8ZI

    N8ZI XML Subscriber QRZ Page

    This Mirage B3016 is my Dad's as I mentioned already.
    I have a RF Concepts Max Amp 10 which does 10w in and just over 180w out. Being it is a different bird, I cannot compare them internally.
    I would let Dad borrow mine while I repair his (as I never use it) BUT I cannot trust him to remember maximum drive power is 10w. Knowing him he will smoke it with 50w input then blame me for it.
     
  5. WB3BEL

    WB3BEL Ham Member QRZ Page

    Maybe just add that wire back and see if it is OK before doing anything else. But that wire getting burned is pretty weird.
     
    N8ZI likes this.
  6. N8ZI

    N8ZI XML Subscriber QRZ Page

    If your amp only has a wire there, then mine will only get a wire there.
    Oddly enough it puts out full power without that section connected.
    Confusingly enough the schematic does show it at the ANT connector right next to the inductor and the burnt gap would be about the correct size for that rated cap.
    If it was just a wire, that amount of wire to be vaporized would require a strong surge and lead me to believe other components would give up the smoke.
     
  7. KA9JLM

    KA9JLM Ham Member QRZ Page

    After looking closer, It does look like the ground wire is broke.

    Not sure why that would happen, Unless the board was removed, Or maybe mobile vibration.
     
    Last edited: Aug 21, 2019
  8. WB3BEL

    WB3BEL Ham Member QRZ Page

    Yes I took that picture of the wire at the connector on my amp in post #15. There is only the wire from the connector ground lug to the PCB ground, and the coil from the antenna connector center conductor to the ground lug.
     
    N8ZI likes this.
  9. N8ZI

    N8ZI XML Subscriber QRZ Page

    Yes I rotated your photo in sync with mine
    and it clearly shows only the inductor and the wire from ANT ground to board ground. The 2pf cap is not where the schematic shows it gggrrrr. It is about 8" away on the other end of the coax !!
    Thanks again and again for your time and photos. You are a huge asset in solving this dilemma.
    If I had just paid closer attention to your second photo, I would have been in touch with reality lol.
    I'll blame it on sniffing the mixed gas fumes while I rebuilt the weedwackers :)
     

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  10. N8ZI

    N8ZI XML Subscriber QRZ Page

    While I have his amp I will add a pair of muffin fans for his long winded "Purple Crystal" award winning transmissions !!

    73 everyone and thanks for the assistance.
    de N8ZI Tom dit dit
     

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